How to check if a value exists in an object using JavaScript - Stack Overflow

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I have an object in JavaScript:

var obj = {
   "a": "test1",
   "b": "test2"
}

How do I check that test1 exists in the object as a value?

I have an object in JavaScript:

var obj = {
   "a": "test1",
   "b": "test2"
}

How do I check that test1 exists in the object as a value?

• javascript

Share Improve this question Follow edited Jul 9, 2020 at 19:46 Peter Mortensen 31.6k2222 gold badges109109 silver badges133133 bronze badges asked Mar 11, 2016 at 19:47 Brown KLBrown KL 2,38344 gold badges1717 silver badges1818 bronze badges 0

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23 Answers 23

Sorted by: Reset to default 184

You can turn the values of an Object into an array and test that a string is present. It assumes that the Object is not nested and the string is an exact match:

var obj = { a: 'test1', b: 'test2' };
if (Object.values(obj).indexOf('test1') > -1) {
   console.log('has test1');
}

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/values

Shortest ES6+ one liner:

let exists = Object.values(obj).includes("test1");

You can use the Array method .some:

var exists = Object.keys(obj).some(function(k) {
    return obj[k] === "test1";
});

Try:

var obj = {
   "a": "test1",
   "b": "test2"
};

Object.keys(obj).forEach(function(key) {
  if (obj[key] == 'test1') {
    alert('exists');
  }
});

Or

var obj = {
   "a": "test1",
   "b": "test2"
};

var found = Object.keys(obj).filter(function(key) {
  return obj[key] === 'test1';
});

if (found.length) {
   alert('exists');
}

This will not work for NaN and -0 for those values. You can use (instead of ===) what is new in ECMAScript 6:

 Object.is(obj[key], value);

With modern browsers you can also use:

var obj = {
   "a": "test1",
   "b": "test2"
};

if (Object.values(obj).includes('test1')) {
  alert('exists');
}

Use a for...in loop:

for (let k in obj) {
    if (obj[k] === "test1") {
        return true;
    }
}

You can use Object.values():

The Object.values() method returns an array of a given object's own enumerable property values, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).

and then use the indexOf() method:

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

For example:

Object.values(obj).indexOf("test") >= 0

A more verbose example is below:

var obj = {
  "a": "test1",
  "b": "test2"
}


console.log(Object.values(obj).indexOf("test1")); // 0
console.log(Object.values(obj).indexOf("test2")); // 1

console.log(Object.values(obj).indexOf("test1") >= 0); // true
console.log(Object.values(obj).indexOf("test2") >= 0); // true 

console.log(Object.values(obj).indexOf("test10")); // -1
console.log(Object.values(obj).indexOf("test10") >= 0); // false

For a one-liner, I would say:

exist = Object.values(obj).includes("test1");
console.log(exist);

I did a test with all these examples, and I ran this in Node.js v8.11.2. Take this as a guide to select your best choice.

let i, tt;
    const obj = { a: 'test1', b: 'test2', c: 'test3', d: 'test4', e: 'test5', f: 'test6' };

console.time("test1")
i = 0;
for( ; i<1000000; i=i+1) {
  if (Object.values(obj).indexOf('test4') > -1) {
    tt = true;
  }
}
console.timeEnd("test1")

console.time("test1.1")
i = 0;
for( ; i<1000000 ; i=i+1) {
  if (~Object.values(obj).indexOf('test4')) {
    tt = true;
  }
}
console.timeEnd("test1.1")

console.time("test2")
i = 0;
for( ; i<1000000; i=i+1) {
  if (Object.values(obj).includes('test4')) {
    tt = true;
  }
}
console.timeEnd("test2")


console.time("test3")
i = 0;
for( ; i<1000000 ; i=i+1) {
  for(const item in obj) {
    if(obj[item] == 'test4') {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test3")

console.time("test3.1")
i = 0;
for( ; i<1000000; i=i+1) {
  for(const [item, value] in obj) {
    if(value == 'test4') {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test3.1")


console.time("test4")
i = 0;
for( ; i<1000000; i=i+1) {
  tt = Object.values(obj).some((val, val2) => {
    return val == "test4"
  });
}
console.timeEnd("test4")

console.time("test5")
i = 0;
for( ; i<1000000; i=i+1) {
  const arr = Object.keys(obj);
  const len = arr.length;
  let i2 = 0;
  for( ; i2<len ; i2=i2+1) {
    if(obj[arr[i2]] == "test4") {
      tt = true;
      break;
    }
  }
}
console.timeEnd("test5")

Output on my server

test1:   272.325 ms
test1.1: 246.316 ms
test2:   251.98 0ms
test3:    73.284 ms
test3.1: 102.029 ms
test4:   339.299 ms
test5:    85.527 ms

you can try this one

var obj = {
  "a": "test1",
  "b": "test2"
};

const findSpecificStr = (obj, str) => {
  return Object.values(obj).includes(str);
}

findSpecificStr(obj, 'test1');

You can try this:

function checkIfExistingValue(obj, key, value) {
    return obj.hasOwnProperty(key) && obj[key] === value;
}
var test = [{name : "jack", sex: F}, {name: "joe", sex: M}]
console.log(test.some(function(person) { return checkIfExistingValue(person, "name", "jack"); }));

In new version if ecma script now we can check vslues by ?. operations..

Its so simpler and easy yo check values in a object or nested or objects

var obj = {
   "a": "test1",
   "b": "test2"
}

if(obj?.a) return "i got the value"

Similarly since in Javascript most used primitive type is Object

We can use this arrays, functions etc too

aFunc = () => { return "gotcha"; }

aFunc?.() // returns gotcha

myArray = [1,2,3]

myArray?.[3] // returns undefined

Thanks

Best way to find value exists in an Object using Object.keys()

obj = {
 "India" : {
 "Karnataka" : ["Bangalore", "Mysore"],
 "Maharashtra" : ["Mumbai", "Pune"]
 },
 "USA" : {
 "Texas" : ["Dallas", "Houston"],
 "IL" : ["Chicago", "Aurora", "Pune"]
 }
}

function nameCity(e){
    var finalAns = []
    var ans = [];
    ans = Object.keys(e).forEach((a)=>{
        for(var c in e[a]){
            e[a][c].forEach(v=>{
                if(v === "Pune"){
                    finalAns.push(c)
                }
            })

        }
    })
    console.log(finalAns)
}


nameCity(obj)

ES2017 introduces a new method called Object.values() that allows you to return an array of own enumerable property’s values of an object.

You can do this to check if the value exists in the Object Values:

let found = Object.values(africanCountries).includes('Nigeria');
if (found) {
     // code
}

You can also check if it exists in the Object Keys:

let found = Object.keys(africanCountries).includes('Nigeria');
if (found) {
     // code
}

getValue = function (object, key) {
    return key.split(".").reduce(function (obj, val) {
        return (typeof obj == "undefined" || obj === null || obj === "") ? obj : (_.isString(obj[val]) ? obj[val].trim() : obj[val]);}, object);
};

var obj = {
   "a": "test1",
   "b": "test2"
};

Function called:

 getValue(obj, "a");

var obj = {"a": "test1", "b": "test2"};
var getValuesOfObject = Object.values(obj)
for(index = 0; index < getValuesOfObject.length; index++){
    return Boolean(getValuesOfObject[index] === "test1")
}

The Object.values() method returned an array (assigned to getValuesOfObject) containing the given object's (obj) own enumerable property values. The array was iterated using the for loop to retrieve each value (values in the getValuesfromObject) and returns a Boolean() function to find out if the expression ("text1" is a value in the looping array) is true.

For complex structures, here is how I do it:

const obj = {
    test: [{t: 't'}, {t1: 't1'}, {t2: 't2'}],
  rest: [{r: 'r'}, {r1: 'r1'}, {r2: 'r2'}]
}

console.log(JSON.stringify(obj).includes(JSON.stringify({r1: 'r1'}))) // returns true
console.log(JSON.stringify(obj).includes(JSON.stringify({r1: 'r2'}))) // returns false

Please refer docs: https://developer.mozilla.org/enUS/docs/Web/JavaScript/Reference/Global_Objects/Object/values

Object.values returns an array and thus any array operation be it array.includes, array.some, indexOF will let you check if the value exists or not.

To check is value exists in each object key in javascript and want to return the object.

let arr = [{
    firstname: "test1",
    middlename: "test2",
    surname: "test3",
    age:20
},
{
    firstname: "test4",
    middlename: "test5",
    surname: "test6",
    age:25
},
{
    firstname: "test7",
    middlename: "test2",
    surname: "test8",
    age:30
}];

let filteredObjects = arr.filter((item) => Object.keys(item).some(key => item[key] === "test2"));

This will return objects by comparing each key pair in each object.

Answer:

[{
    firstname: "test1",
    middlename: "test2",
    surname: "test3",
    age:20
},
{
    firstname: "test7",
    middlename: "test2",
    surname: "test8",
    age:30
}]

Hope this is helpful!

Check the in

const car = { make: 'Honda', model: 'Accord', year: 1998 };

console.log('make' in car);
// Expected output: true

delete car.make;
if ('make' in car === false) {
  car.make = 'Suzuki';
}

console.log(car.make);
// Expected output: "Suzuki"

Source https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/in

I like the solutions, I also added an extended solution for nested objects:

const Person = {
    name: 'Omar', lastname: 'Ruiz', age: 24,
    nested: { attribute: false }
}

function checkValuesRecursively(o, value) {
    if (typeof o === 'object') {
        for (const prop in o) {
            const isValuePresent = checkValuesRecursively(o[prop], value);
            if (isValuePresent) return true;
        }
    } else if (o === value) {
        return true;
    }
    return false;
}

const result = checkValuesRecursively(Person, 24);
console.log(result);

// true

This will check every property on the object recursively to find the value. You can modify a little bit this function to return the name or path of the property that has this value.

_.has() method is used to check whether the path is a direct property of the object or not. It returns true if the path exists, else it returns false.

var object = { 'a': { 'b': 2 } };
console.log(_.has(object, 'a.b')); 
console.log(_.has(object, ['a','b'])); 
console.log(_.has(object, ['a','b','c']));

Output: true true false

The simple answer to this is given below.

This is working because every JavaScript type has a “constructor” property on it prototype”.

let array = []
array.constructor === Array
// => true


let data = {}
data.constructor === Object
// => true

This should be a simple check.

Example 1

var myObj = {"a": "test1"}

if(myObj.a == "test1") {
    alert("test1 exists!");
}

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